Blowing device for rock drills



J. C. CURTIS BLOWING DEVICE FOR ROCK DRILLS Filed March 25. 1932 July l3l, l934.\

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ATTORNEY Patented July 31, 1934 Urrsp STATES BLOWING DEVICE FOR ROCK DRILLS John C. Curtis, Cleveland, Ohio, assigner to The Cleveland Rock Drill Company,

Cleveland,

Ohio, a corporation of Ohio Application March 23,

2 Claims.

'Ihis invention relates broadly to rock drills but is more particularly concerned with a blowing device for rock drills of the uid actuated type.

One of the objects of this invention is to selectively admit an uninterrupted supply of motive fluid under full linepressure to the cuttingtool for cleaning the drilled hole.

Another object of this invention is to provide a structure, wherein a single manipulation of the throttle valve will eiectuate the closing of the exhaust port, and bring the Working piston into a desired position, to allow the supply of the motive uid to the cutting tool.

Other objects and advantages reside in the specic constructionand aggroupment of the elements peculiar to this structure as will become apparent from a more complete examination of this specication, wherein there are assembled and pointed out certain combinations of parts and "specific construction indicative of the scope and spirit of the invention.

In the drawing which'illustrates a preferred embodiment of the invention:

Fig. 1 is a central vertical section through a rock drill embodying the present invention, the different elements therein being shown in their normal operating position. Y

Fig. 2 is a view similar to Fig. 1, illustrating the position taken by the different elements when the apparatus is operated to blow dust and extrane-` ous matter from the hole being drilled.

The rock drill illustrated in the drawing comprises a cylinder 10 having al piston 1l reciprocably mounted therein. The piston 11 is provided with a stem 12 in slidable engagement within a stationary bushing 13. The stem 12 is provided for a portion of its length with a plurality of splines ,1.4 being capable of slidable but nonrotatable engagement within the rearward portion of a chuck 15, which portion is rotatably mounted within the stationary bushing 13, and has its forward portion rotatably mounted within a front housing 16. Internally, the chuck 15 is conveniently machined to slidably but nonrotatably receive the shank 17 of a hollowed cutting tool 18. Intermediate its ends, the chuck 15 is also manufactured with an internal chamber 19, within which the end of the shank 17 projects to receive the striking blows of the piston 11. The chamber 19 is connected to the exterior of the chuck through a plurality of radially disposed orifices 20, the purpose of which will be explained hereafter.

Maintained within the rear end of the cylinder 10, there is a valve block 21, and a valve cap 22,

1932, Serial No. 600,635

conveniently machined to form a valve chamber 23, within which there is reciprocably mounted an inlet fluid controlling valve 24. This valve is provided with fluid actuated areas 25 and 26, and holding area 27. The operation of the valve`24 is identical to the one described in my co-pending application filed November 9th, 1931, Serial Number 573,921, and since this valvular mechanism is no part of the present invention, no further de# scription of same is thought necessaryl f Intermediate its ends, the wall of the cylinder 1'0 is provided with a restricted cylindrical bore or exhaust chamber 28, within whichy there is reciprocably mounted on exhaust controlling valve or pressure actuated valve 29. Equally spaced from its ends, this valve is provided with an annular recess 30. The exhaust chamber 28 is in constant communication with the interior of the cylinder 10 through an enlarged exhaust passage 31. and with the atmosphere through a similar passage 32. The rearward end of the cylinder 10 may be vented-to atmosphere through a restricted port 33, which loads into the exhaust chamber 28,

and is adapted to be covered by the exhaust valvev t 29. f To effectuate a positive reciprocation of the iiuid controlling valve 24,- the cylinder 10 is provided within its walls with a kick port 34, having one of its ends opening into the cylinder above the exhaust port 31; the other end of this port is in constant registration with an annular groove 35, formed within the valve block 21, and is capable of conveying pressure fluid to the valve holding area 27, through a plurality of ports 36.

Disposed rearwardly of the valve block 21, there is a rotation mechanism comprising a ratchet ring 37, and a rifled stem 38, extending through the valvular mechanism into the piston 11, for imparting rotation thereto. The riiied stem 38, and its appurtenances is maintained within the ratchet ring 2l, by a bearing plate 39, which is secured in abutting relation with the ratchet ring 37, by a backhead 40, clamped to the cylinder by a pair of side bolts (not shown).

Transversally disposed Withinthe backhead 40, there is a cylindrical chamber 41, within which there is rotatably mounted in iluid tight engage-'- ment therein a throttle valve 42, formed with a central bore 43, in constant communication with a motive fluid source of supply. Leading from the throttle valve chamber 41 into the forward portion of the machine there is an enlarged passage 44 in constant communication with the radially disposed orifices 20 through a circumferloo its

- as will be explined hereafter.

ential clearance 45, provided between the chuck 15 and the front housing 16.

The bearing plate 39 is provided with an enlarged circular recess 46, which is in constant communication with the throttle valve bore 4l, through an enlarged passage 47, and with the fluid controlling valve chamber 23, through a plurality of passages 5l. From this chamber 23, motive fluid may be admitted into the forward end of the cylinder 10, through a plurality of passageways 48, and into the rear end of the cylinder l0, through a plurality of passages 49.

The rearward end of the exhaust valve chamber 28 is in constant communication with the throttle valve chamber 41 through a restricted port 50, and the forward end of this chamber is in constant communication with the enlarged. passage 44 through a restricted port 52, circumferential recess v53 and port 54.

The throttle valve 42 is provided with a plurality of radially disposed passages 55, 56, and 57, disposed in different vertical plane and capable of admitting motive fluid from the central bore 43 into the different ports of the machine Provided on the external wall of the throttle valve 42, there is a groove 58 capable of registration with the restricted port 50 and vent 59.

During the operation of the machine, the throttle valve 42 is positioned in such a way as to permit the registration of the throttle valve passage 57 with the enlarged passage 47 which is disposed on the same vertical plane. Motive fluid may then be admitted into the inlet controlling valve chamber 23 from the bore 43, throttle valve passage 57, enlarged passage 47, recesses 46 and passages 51. Controlled by the inlet fluid controlling valve 24, motive fluid is Vistributed into the front and rear end of the cylinder 10 throughthe passage 48 and 49, affording the reciprocation of the piston 11 and the consequential distribution of its blow upon the free end of the cutting tool 18. lt will be observed that with the throttle Valve in this position, the vent 59 is closed by the throttle valve and the restricted passage 50 is in communication with the motive fluid source of supply or bore 43 through throttle valve passage 55, thus admitting motive fluid into the rearward end of the exhaust chamber 28 Via port 55, and port 58. Motive fluid admitted into the exhaust chamber 28 will exert pressure upon the rearward end of the valve 29 and hold the same in the position illustrated in Fig. l. The forward end of the chamber 28 is exhausted to atmosphere through the restricted passage 52, circumferential recess 53, port 54, enlarged passage 44, circumferential clearance 45 and radially disposed ports 20 into the chamber 19 and through the drill steel 18. With the exhaust controlling valve 29 in this position, motive fluid may exhaust from the cylinder 10 to atmosphere through the exhaust port 31, recess 3G and port 32.

When it is desired to blow the hole being drilled, the throttle valve may be turned into a position as illustrated in Fig. 2. Motive fluid may now be admitted into the chamber 19 through the throttle valve passage 55, enlarged passage 44, circumferential clearance 45 and radially disposed orifices 29. Simultaneously motive fluid from the enlarged passage 44 will flow into the forward end of the exhaust chamber 28 through port 54, circumferential recess 53 and restricted port 52, thus creating pressure upon the exhaust valve 29 and shifting the same rearwardly to close the exhaust port 31. The motive fluid previously admitted into the rearward end of the chamber 28 is now exhausted to atmosphere through the restricted port 50, throttle valve groove 58 and vent 59. With the exhaust valve 29 in the rearward position, the rear end of the cylinder 10 is exhausted to atmosphere through the restricted passage 3S, annular groove 30 and exhaust passage 33. Simultaneously motive fluid is admitted into the inlet controlling Vvalve chamber 23 through the throttle valve passage 55, passage 47, circular recess 48 and passages 51. The flow of motive iluid upon the valve 24 will hold the valve forwardly thus allowing motive fluid to be admitted into the forward end of the cylinder 10 through the passages 48 to drive lthe piston 11 rearwardly, the rearward end of the cylinder 10 being exhausted to atmosphere through the restricted passage 33, as explained previously. The inlet controlling valve is maintained in this forward position by motiveY fluid exerting pressure upon the actuating area 26 and holding area 27 through the kick port 34, annular groove 35 and ports 36.

Motive fluid being admitted into the front end of the cylinder l0 will flow into the chamber 19 through the openings provided by the splines 14 formed upon the forward position of the piston stem 12. From the chamber 19 the pressure fluid will flow to the bottom of the hole being drilled through the central aperture provided within the drill steel 18, thus cleaning or blowing the drilled hole. It will be noted that due to the double inlet of pressure fluid to the chamber 19, a great amount of fluid may be supplied to that chamber, thus increasing the pressure therein and affording an efficient blowing device.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or confining and it is to be further understood that various rearrangements of parts and modification of structural detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

1. In a fluid actuated machine, a cylinder having a piston reciprocable therein formed with a iluted stem, a hollow drill steel slidably mounted within the front end of said machine capable of engagement with said stem, passages for alternatively admitting pressure fluid into both ends of said cylinder for normally actuating said piston, an exhaust port for said cylinder, an exhaust valve capable of closing said exhaust port normally held open by the action of the pressure fluid admitted on one end thereof, a vent leading from one end of said cylinder and normally closed by said exhaust valve, another passage for admitting pressure fluid to the end of said stem and drill steel and to the other end of said exhaust valve, a throttle valve movable in one position for admitting pressure fluid into said cylinder for actuating said piston and on one end of said exhaust valve for maintaining the latter in open position, said throttle valve being movable in another position for venting said first mentioned end of said exhaust valve and simultaneously admitting pressure fluid on the other end thereof through said other passage for shifting the latter in exhaust port closing position, opening thereby said vent for permitting the exhaust of the pressure fluid Sil from said one end of said cylinder, said throttle valve While in said last mentioned position also admitting pressure fluid to the end of said stern and drill steel through said other passage for admitting pressure uid via said drill steel to the bottom of the hole being drilled and into said cylinder Via the liutes of said stem for shifting said piston into the vented portion of said cylinder for maintaining said stem in spaced relation with said drill steel.

2. ln a fluid actuated machine, a cylinder having a piston reciproeahle therein formed with a fluted stem, a hollow drill steel slidably mounted Within the front end of said machine Capable of engagement with said stern, a fluid actuated Valve for controlling the admission of the pressure fluid into said cylinder for actuating said piston, an exhaust port for said cylinder, an exhaust valve capable of closing said exhaust port and normally held open by the action of the pressure iiuid admitted on one end thereof, a Vent leading from one end of said cylinder normally closed by said exhaust valve, a passage for admitting pressure fluid t0 the end of said drill steel and to the other end of said exhaust Valve, a throttle Valve movable in one position for admitting pressure fluid to said fluid actuated valve and to one end of said exhaust valve for maintaining the latter in open position, said throttle valve being movable in another position for admitting pressure fluid to said uid actuated valve and simultaneously Venting one end of said exhaust Valve and admitting pressure fluid through said passage to the other end of the exhaust valve for shifting the latter in exhaust port closing position, opening thereby said vent for exhausting one end of said cylinder and simultaneously holding said fluid actuated valve in one position for admitting pressure fluid to the front end of said cylinder for shifting said piston into the exhausted end of said cylinder and admitting pressure uid from said front end of said cylinder Via the flutes of said piston stem to the end of said drill steel, said throttle Valve While in said last mentioned position also admitting pressure fluid to the end of said drill steel through said passage for cooperating with the pressure fluid admitted thereto via the piston utes for blowing the hole being drilled.

JOHN C. CURTIS. 

